I'm always messing around making targets for air guns. So many I've' forgotten where I've put them and what I've made. They turn up in a storage garage all the time. This weekend I was making 100 yard targets and some metal hanging balls for closer range. Pretty simple bend a U frame and weld some nuts to the ends to hold the target bar.
They fold flat for transport.
I like electrical boxes to use for a rubber landscape mulch holder. I cut a hole a little smaller than a standard size paper.
When the box is filled with mulch I put a piece of cardboard on top and the target page on top of that. Close the lid and it's held firmly in place. When it's shot up I replace the cardboard and shoot it up again.
Some boxes have their own lock, others I just add a hasp.
Nice work! I especially liked the ritz crackers idea. I'm doing research now and mulling over options. I've been mulling over some sort of IDPA-ish steel target for dust devils (probably without the head), and maybe a center clanger so you can tell from sound if you're in the high scoring part.